Monday, February 18, 2008

This one is for the wine geek in us all. Wine is spoiled grape juice. The initial spoilage is caused by yeasts that turn grape sugar into alcohol and carbon dioxide. This vigorous and exciting process is called primary fermentation. Later secondary fermentation called malolactic fermentation, is caused by friendly wine bacteria. They convert malic acid (think sour green apples) to lactic acid (think the mouth experience of melted butter or milk) and carbon dioxide. It is usually encouraged in red wines and discouraged in whites. If it occurs after a wine is in a bottle the wine can get a little fizzy – generally considered a wine fault. In this picture I’ve used paper chromatography to figure out if a wine has gone through malolactic fermentation. Small drops of each wine are deposited at the bottom of the page. As the diluent travels up the fancy blotter paper, it takes with it the primary acids that are present in wine. The lowest yellow blotch is tartaric acid. The middle yellow blotch is malic acid and the upper most yellow blotch is lactic acid. The wines to the left of the paper have only tartaric and lactic acid blotches – voila, done! The wines toward the right have all three yellow spots. That would be five of the six barrels of Sangiovese clone 2. They are not done yet, but once the weather warms up those little bugs will get happy again and finish the job.